A railroad frog is a device which is installed at the intersection of two running rails to permit the flanges of railroad car wheels moving along one of the rails to pass across the other rail. The frog supports the car wheels as they pass over the missing rail tread surface between the throat and the point of the frog, and also provides flangeways for the flanges of those car wheels which pass through the frog.
A railroad spring wing rail frog assembly typically includes a rigid wing rail, which is substantially aligned with a long point or heel rail element connected to a turnout traffic rail, and a relatively movable spring wing rail which is substantially aligned with a short point or heel rail element that is connected to a main line traffic rail. The movable wing rail is mounted with a yieldable free end, provides a substantially continuous support for the wheels of a rail car passing along the main line track, and often is closure-biased toward the frog long point rail by including a compression spring-type wing rail-closer element to the frog assembly. The movable wing rail, sometimes called a spring wing rail, has inherent lateral resiliency and is moved laterally away from the long point rail to provide a wheel flangeway between the long point rail and the spring wing rail when a railcar wheel flange traversing the rigid wing rail engages the spring wing rail free end and forces or causes that rail to be moved laterally to a full open position. After the last co-operating railcar wheel has passed through the assembly, the compression forces induced in the wing rail by bending and by the added rail-closer element cause the movable wing rail to be forcefully moved into its normal abutting relationship with the frog assembly long point rail.
U.S. Pat. No. 4,624,428, issued in the name of Frank, U.S. Pat. No. 5,544.848, issued in the names of Kuhn et al., and U.S. Pat. No. 5, 810,298, issued in the names of Young at al., all assigned to the assignee of this application, each disclose details of representative railroad spring wing rail frog assemblies known and utilized in the United States. While such frog assemblies have satisfactorily fulfilled different railroad trackwork application requirements, it has been observed that in instances in which the frog assemblies include a hold-open subassembly (sometimes also referred to as a holdback device) the frogs have been subjected to spring wing rail "overshooting" as a result of repeated, large-amplitude impact forces being imposed on the spring wing rail by the wheel flanges of railcar wheels moving through the assembly--especially at higher train velocities. The "overshooting" phenomenon can result in both frog assembly excessive wear and in possible substantial damage to the hold-open device.
We have discovered a new and useful railroad trackwork frog assembly construction which will improve frog assembly performance by eliminating the unwanted spring wing rail overshooting that often results from repeated high-impact forces being applied to she spring wing rail by successive railcar wheel flanges.
Other objects and advantages of the present discovery will become apparent during a careful consideration of the invention summary, description of the drawings, and detailed description which follow.